How Blackouts during Heat Waves Amplify Mortality and Morbidity Risk

Area of Science:

• Environmental science
• Public health
• Urban planning

Background:

• Extreme heat events and electrical grid failures are increasing.
• These events compound risks to population health during extreme weather.

Purpose of the Study:

• To assess how concurrent electrical grid failures during heat waves affect heat-related mortality and morbidity.
• To estimate personal-level heat exposure changes accounting for indoor and outdoor environments.

Main Methods:

• Combined simulated heat exposure data from historical heat waves in three U.S. cities.
• Developed a novel method for estimating hourly, individually experienced temperatures.
• Accounted for both outdoor and indoor building exposures.

Main Results:

• Concurrent grid failures during heat waves more than doubled estimated heat-related mortality.
• Medical attention was required for 3% (Atlanta) to over 50% (Phoenix) of urban populations.
• Impacts were observed across present and future time periods.

Conclusions:

• Enhanced electrical grid resilience is crucial for mitigating heat-related health impacts.
• Increased tree canopy and high albedo roofing can reduce heat exposure during compound events.
• Proactive urban planning is essential for climate adaptation and infrastructure failure preparedness.